Surface mapping and generating devices and methods for surface mapping and surface generation

ABSTRACT

A surface mapping and generating device which has devices for the process and/or cost optimization, in particular raw material recovery devices, an automatic control of the intensity of a used laser light, devices for carrying out a calibrating procedure by evaluating overlap errors at matching points, devices for archiving especially three-dimensional data of the jaw and/or for modeling the bite position of the upper and the lower jaws, devices for the optimized preparation of at least one dental stump for the production and placement of a dental prosthesis thereon and/or devices for taking into consideration the bite position of the upper and lower jaws. It can be provided that the devices for the process and/or cost optimization are designed to ensure that two half frames showing different positions or views are evaluated, whereby preferably a pulsed laser for exposure purposes is included and/or that an image recording device, in particular a CCD chip, is arranged so as to ensure that lines, taking into account the Scheimpflug angle, are located perpendicular to the direction of travel of a measuring table. Methods according to the present invention use such devices and function correspondingly. In addition, the invention also makes available a patient data archiving system which comprises a chip card and/or decentralized data storage systems especially for dental data.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/026,617, filed on Feb. 6, 2008, which in turn is a continuation ofU.S. patent application Ser. No. 10/427,731, filed May 1, 2003, now U.S.Pat. No. 7,399,181 B2, issued on Jul. 15, 2008, which in turn is acontinuation of International Application No. PCT/DE01/04177, filed Nov.8, 2001. The aforementioned applications are hereby incorporated byreference in their entireties. The information incorporated is as much apart of the instant application as filed as if the text was repeated inthe application, and should be treated (the incorporated information) aspart of the text of the application as filed.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a surface mapping and generatingdevices and to methods of surface mapping and surface generation. Inparticular and preferably, the present invention relates to devices andmethods for mapping and/or generating surfaces of teeth.

2. Prior Art

The state of the art is exemplified by a prior-art device for theproduction of a dental prosthesis according to European Patent EP98115809.0, and the technology disclosed in German Patents DE 44 39 307A1 and DE 197 21 688 A1.

SUMMARY OF THE INVENTION

The basic technologies on which the present invention is based or withwhich it can be combined are disclosed in the German Patent Applications[Offenlegungsschrift] DE 44 39 307 A1 and DE 197 21 688 A1, which areused as the closest prior art, on the one hand, and which, by referenceare hereby fully incorporated in the present documents, since thepresent invention in all of its embodiments is based on this technology,continues to develop and/or improves it advantageously, on the otherhand, which is the objective of all of the aspects of the presentinvention.

This objective is implemented using devices and methods according to theclaims. In particular, the invention makes available a surface mappingand generating device with devices for the process and/or costoptimization.

It is preferable for the process and/or cost optimization devices tocomprise raw material recovery devices; also, it is preferable for theprocess and/or cost optimization devices to be able to automaticallycontrol the intensity of a laser light used. As an alternative or inaddition thereto, it is preferable for the process and/or costoptimization devices to be designed so as to make it possible toevaluate two half frames which display different positions or views,comprising for this purpose especially a pulsed laser for exposurepurposes.

Other alternative or additional embodiments of a surface mapping deviceaccording to the present invention, in particular for obtaining surfacedata of teeth, provide that the devices for the process and/or costoptimization comprise devices for carrying out a calibration procedureby evaluating overlap errors at matching points and/or that animage-recording device, in particular a CCD chip, is arranged so as toensure that lines, taking into account the Scheimpflug angle, arelocated perpendicular to the direction of travel of the measuring table.

Another variation of a surface mapping device, in particular forobtaining surface data of teeth according to the present invention,provides that the devices for the process and/or cost optimizationcomprise devices for archiving especially three-dimensional data of thejaw and for modeling the bite position of the upper and lower jaws.

Special, preferably mechanical, embodiments of the surface mappingdevice are based on the disclosure contents of FIGS. 3 and 4 and/or 5,6, and 7 and on the description associated with these figures.

Moreover, it is to be preferred if, in the surface mapping andgenerating device especially for the production of dental prostheses,the devices for the process and/or cost optimization comprise devicesfor an optimized preparation of at least one tooth stump for theproduction or placement of a dental prosthesis thereon and/or devicesfor taking into account the bite position of the upper and lower jaws.

The surface mapping and/or generating methods for reaching theabove-mentioned objective of the present invention are characterized inthat they use one or a plurality of the devices described above andfunction correspondingly.

Finally, the present invention also makes available a patient dataarchiving system which is marked by a chip card and/or decentralizeddata storage systems, in particular for dental data.

Certain aspects of this invention will be explained in greater detailbelow.

According to one aspect of the present invention, it is provided thatraw material is recovered based on the surface mapping technologies,devices, and methods, such as are described in the above-mentionedpublications which are hereby incorporated by reference into the presentinvention, hereinafter simply called “scanners” and “scanning,” incombination with, for example, a milling machine. The scanner, incombination with the milling machine and a suitable electronic dataprocessing (EDP) device, forms a CAD-CAM system, in particular for theproduction of dental prostheses made of gold or platinum. The recoveryof raw material can be preferably implemented by providing that, forexample, the milling machine used is equipped with devices, e.g., forsiphoning off gold or platinum dust or chips. Considering the high costof the raw materials, such as gold or platinum, this resultsadvantageously in a considerable reduction of the cost for theproduction of dental prostheses made of gold or platinum.

According to another aspect of the present invention, the scannertechnology disclosed in the publications cited above is furtherimproved.

This is made possible, on the one hand, by an automatic control of theintensity of the laser light used. To implement this, the reflectivity,for example, of the surface of the tooth to be mapped is determined byway of the intensity of the light that is, e.g., recorded by a CCD chip.Based on the result of the determination, the intensity of the laserlight is subsequently readjusted. The improvement of this embodiment isto be seen in the fact that this reduces measuring errors due to anunder- or overcontrol of the measured signals. The present inventionalso relates to devices and methods associated with the descriptionabove.

The scanner technology of the present invention is improved, on theother hand, by an increase in speed in that, instead of a full frameconsisting of two composite half frames, two such half frames which showdifferent views are evaluated by the camera or the CCD chip. Thedifferent views are obtained by different positions of the surface, forexample, of a tooth relative to the device for recording this surface(e.g. a camera with a CCD chip or a CCD chip alone).

It is possible to advantageously further develop, in particular, theimprovement mentioned above and, quite generally, the scanningtechnology used in that the laser used is triggered by pulses, similarto a stroboscopic effect, and that, for example, the table which holdsthe object, the surface of which is to be mapped, such as a tooth or amodel of a tooth, is, in particular, continuously moved. Because of thepulsed laser beam, snapshots or “still images” of each position of theobject relative to the camera are recorded, since during the short timeof exposure to a laser beam pulse, the object appears to stand still ina certain position and, in this position, can be recorded by the camera.It is to be especially preferred if each individual laser pulse isassociated with the recording of a half frame.

Yet another improvement of the scanner technology according to thepresent invention concerns a calibrating procedure which correctsdifferent spatial distortions of the measured quantities obtained. Toimplement this, a body is scanned from different angles. Themeasurements are assembled by means of a matching algorithm. The overlaperrors which are produced at different points of the object when thesemeasurements are assembled are analyzed so as to ensure that variationsin all spatial directions are detected. These variations lead tocalibration errors from which, in turn, calibration parameters can becalculated in all spatial directions and spatial rotations. In thecourse of subsequent measurements, these calibration parameters can thenbe automatically taken into consideration by the EDP unit, whichadvantageously contributes to an increased precision of measuring.Further details related thereto follow from the practical example shownin FIG. 1.

The prior-art scanner technology mentioned above is further improved bythis invention in that a CCD chip (or, generally, a surface imagerecording device) is arranged so that, for example, camera lines, takinginto account the Scheimpflug angle, are positioned so as to beperpendicular, e.g., to the direction of travel of the measuring tableon which the object to be scanned is placed. Further details relatedthereto are illustrated in greater detail in the practical example shownin FIG. 2. This makes possible an improved utilization of the measuringarea for scanning, for example, teeth, but it should be remembered thatcommercially available chips are not square.

The conventionally known scanner technology can be even further improvedin that the present invention provides for the configuration oftraveling and pivoting axes for the object carrier, the object and/orthe camera so that it is possible to view all undercuttings present inthe jaw when the invention is used, e.g., for mapping the dentalsurface. The advantage is that a fully automatic scanning/measuringstrategy can be used.

According to another aspect of the present invention, different EDPmodules are advantageously used, for example, in different fields ofdental medicine.

Thus, the present invention makes available a scanner technology whichcomprises an EDP system, preferably in the form of a standard computerwith special software as the control device, which is suitable forarchiving, e.g., three-dimensional data of the jaw, in particularsurface data. This archiving system serves as a substitute for previousforms of systems for archiving such data in the form of plaster models.In many areas of dental medicine, it was previously necessary to retainthe plaster models of patients' teeth for a period of up to 10 years,which required an enormous space for storage. Archiving these dataelectronically, however, not only eliminates the need for a largestorage space but also makes it possible to utilize the archived datamore rapidly, more easily, and at considerably lower cost. Thus, it ispossible, for example, to record and archive 3-D measuring data ofpreviously healthy dental surfaces. As a result, years later, e.g., whena tooth needs to be replaced, the tooth can be reconstructed in the formof a dental prosthesis which, for example, can be produced by millingits surfaces on the basis of the archived data.

An electronic archiving system for jaw and/or dental data, however,provides for many other additional advantageous uses as well. Thus,these data can be processed by means of a suitable EDP system to modelthe original bite position of the upper and the lower jaws. Inparticular, this can be accomplished by first scanning the lower jaw, bysubsequently placing a check bite (impression in the patient's mouthwhile he or she bites down) on the lower jaw, and by scanning it again.Thus, both dental surfaces in the bite situation are recorded. Both datarecords can be viewed separately or in combination with each other, andall dental analyses associated therewith can be carried out, forexample, qualitatively or quantitatively (in the form of distance orvolume measurements). To complete the measurement, the entire upper jawcan be scanned and spatially referenced by means of the check bite and,for example, matching software. Furthermore, it is possible to alsosimulate masticatory motions on the computer by means of recording themovement of the jaw and the bite check. Referencing the measured data ofthe upper and the lower jaws can also be used to modulate dentalprostheses in connection with the CAD-CAM technology.

An additional variation of the present invention relates to a scannertechnology which comprises an EDP system, such as a standard computerwith a suitable type of software as the control device, with which thebite position of the upper and lower jaws can be modeled particularlyfor orthodontic surgery. The treatment plan, for example, for installinga dental brace, can be simulated in that, for example, in the software,the teeth are divided into dental groups, down even to individual teeth.Such groups and/or individual teeth can be moved and the final positionscan be simulated. This provides answers to questions, such as whetherthere is enough room on the alveolar ridge and how the bite will lookafter the treatment. The treatment can be controlled by means of otherEDP and software systems which can be modularly combined. At certainintervals, a jaw can be rescanned again and again. The successivechronological images can subsequently be shown as an interpolated“film.” This makes it possible to compare the progress of the actualtreatment with the planned treatment and to identify and carry outcorrections. Furthermore, these series of images can be archived andcan, for example, be used as evidence in cases of law suits. Inaddition, these images also facilitate and expedite the communicationwith expert witnesses and insurance companies.

Another aspect of the present invention is related to a scannertechnology which comprises an EDP system and an electronic control (forexample, by means of software) so as to be able to model, e.g., the biteposition of the upper and the lower jaws particularly for orthodonticsurgery. This aspect of the present invention makes it possible, inparticular, to incorporate the measured data of the jaw bones(determined, e.g., by means of computed tomography) using a suitablematching software. The planned treatment (e.g., an operation of the jaw)is simulated in that, for example, in a software, the teeth, the jaw,and the jaw bone are divided into groups of tooth and jaw sections (downto individual teeth). The groups and/or individual teeth can be movedand the final positions can be simulated. This makes it possible toanswer questions, such as whether the space required is in fact presentand how the patient will look after the treatment. In this case, anotherEDP and software module can be used for follow-up treatment. At certainintervals, each respective current status is scanned. The images takenover time can be displayed in the form of an interpolated “film.” Theprogress of the actual treatment can be compared to the plannedtreatment, and based on this comparison, potentially requiredcorrections can be made. This aspect of the present invention makes itpossible to advantageously plan and simulate implants. Among the otherbenefits worth mentioning is the fact that series of archived images canbe used as evidence in cases of potential law suits and that thecommunication with expert witnesses and insurance companies is madeeasier and faster.

The scope of the present invention also extends to a patient datacarrier, such as a chip card, which contains all data relating to aperson's health and illnesses. Such an individual data carrier can beintegrated into an administrative and archiving system which comprises,in particular, decentralized storage systems for archiving largequantities of data which can be accessed by means of accessing means onthe data carrier. Thus, it is possible to archive and make readilyavailable, for example, basic dental patient data which can include the3-D data of the jaw and individual teeth and their dental surfaces aswell as internal structures of individual teeth and data on theproduction of dental prostheses used (data on material and, e.g.,milling). In addition, data on health insurance, digital X-rays,formerly and presently attending physicians, and, in general, the entirepatient history can be stored on said data carrier. The scope of thepresent invention also extends to special reading and evaluating unitswhich may also be integrated into the system. Thus, among the advantagesobtained are double archiving for patients, improved retrospectivefollow-up means for insurance companies, and the availability of dataeven if the patient changes his or her address.

Furthermore, the subject matter of the present invention also relates toanother variation or embodiment which allows for the implementation of apulsed measurement, the basic principle of which had already beenmentioned earlier.

A suitable surface mapping device or system comprises, for example, alinear table, a CCD camera, a frame grabber card, and a laser linemodule. To obtain the data, the laser line is projected continuously onthe object to be measured. The measuring table moves the object step bystep through the measuring arrangement (laser line and CCD chip). Aftereach step, a measurement is carried out.

The method was previously carried out as follows: The measuring tablemoves into a starting position and stops. The object must be at rest toensure that the picture taken is not “blurred,” which can lead toimprecise measurements. Subsequently, the CCD camera reads out a line(full frame) and transmits the signal to the frame grabber card. Next,the table is accelerated (approach ramp). Then the table is slowed downand stopped in a predetermined position (braking ramp). The CCD cameranow reads out the next line. This entire process takes place in completedarkness. The laser diode can be regulated only to a specific output toensure that the signal is not overcontrolled.

The novelty of the present invention is that the laser line is projectedin a stroboscope-like fashion onto the object to be measured, whichmeans that light flashes in the form of a laser line are projected atregular intervals onto the object. The measuring table moves the objectcontinuously through the measuring arrangement (laser line, CCD chip).With each light flash, a measurement is simultaneously carried out. Inparticular, the measuring table moves at a controlled/supervised speedwhich is adjusted to the flash control. At preferably regular intervals(time or travel path of the table), a flash is emitted, and at the sametime, a half frame of the CCD chip is read out. This signal istransmitted to the frame grabber card and evaluated by means of specialsoftware. The flash time is so short that any “blur” potentially causedby the continuous movement of the table is negligible.

As a result of the embodiment of the invention just mentioned, themeasuring process is accelerated by a factor of 5 since the approach andbraking times of the table are eliminated and the light flashes can betimed fast enough so that the readout can take place with half frames.An additional advantage is that the control device can have a lessexpensive design since only a uniform advance is required and no preciseresting position has to be set. Another advantage is that theoptomechanical configurations formerly used can continue to be usedsince the novelty exists or can be implemented with regard to theopen-loop control, the closed-loop control, and the software for thecomponents. Another advantage is that the intensity of the flash used isconsiderably higher than the formerly used laser signal, as a result ofwhich it is possible to carry out the measurement even in daylight,without having to darken the measurement room, which considerablyreduces the labor and time expenditure especially when exchangingobjects to be measured.

In addition to the technical specifications for the “stroboscopiclaser,” etc., already described above, the scope of the presentinvention also extends to mechanical designs which are considered worthprotecting or capable of protection, both as far as the underlyingconcept is concerned and as to the actual embodiments and operatingprocedures in combination with each other or each by itself.

Especially when compared to the prior-art device for the production of adental prosthesis according to European Patent EP 98115809.0, thepresent invention is marked by a number of concepts and designs whichdramatically reduce the cost of producing such a device and make itfunction more reliably. In addition, these aspects of the presentinvention constitute advantageous and preferred further developments andcombinations of the technology disclosed in German Patents DE 44 39 307A1 and DE 197 21 688 A1, the entire contents of which as well as thecontents of the European Patent Application EP 98115809.0 are herebyfully incorporated by reference into the present documents to avoid mereidentical repetitions. In particular, the individual characteristics andcombinations of characteristics can, but need not necessarily orexclusively be, combined with the stroboscopic technique describedabove.

With the individual aspects of the present invention, above all,technical improvements over and above the technical teaching in EP98115809.0 are made available, with these improvements being specific,without being restrictive.

Other preferred and advantageous embodiments of the present inventionfollow from the individual claims and combination of such claims.

Below, the present invention will be explained in greater detail only byway of practical preferred embodiments with reference to the drawings,with these embodiments being no more than possible examples.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING

As can be seen:

FIG. 1 a shows a diagrammatic top view of a jaw in which prior-artscanning lines are sketched in;

FIG. 1 b shows a diagrammatic front view of a jaw in which the scanninglines according to FIG. 1 a are sketched in;

FIG. 1 c shows a diagrammatic top view of a jaw in which scanning linesaccording to the present invention are sketched in,

FIG. 1 d shows a diagrammatic front view of a jaw in which the scanninglines according to FIG. 1 c are sketched in;

FIG. 2 a shows a diagrammatic perspective view of an object to bemeasured in the form of a tooth;

FIG. 2 b shows a diagrammatic view of the object to be measured of FIG.2 a in which prior-art scanning lines are sketched in;

FIG. 2 c shows a diagrammatic view of a signal image of a scanning lineof FIG. 2 b;

FIG. 2 d shows a diagrammatic view of the object to be measured of FIG.2 a in which the scanning lines according to the invention are sketchedin;

FIG. 2 e shows a diagrammatic view of a signal image of a scanning lineof FIG. 2 d;

FIG. 3 shows a perspective diagrammatic view of a practical example of asurface mapping device from an oblique angle from above;

FIG. 4 is an enlarged representation of one portion of FIG. 3;

FIG. 5 shows a perspective diagrammatic view of the practical example ofthe enlarged surface mapping device of FIG. 3 from an oblique angle fromabove in a different setting;

FIG. 6 shows a perspective diagrammatic view of the practical example ofthe enlarged surface mapping device of FIG. 3 from an oblique angle frombelow;

FIG. 7 shows a perspective diagrammatic view of the practical example ofthe enlarged surface mapping device of FIG. 3 from an oblique angle frombelow, the device having been slightly rotated relative to the viewshown in FIG. 6;

FIG. 8 is a graphic representation of a jaw with diagrammaticallysketched-in positions of measuring lines on the basis of data that werescanned in according to the present invention;

FIG. 9 is a graphic representation of the jaw with teeth of FIG. 8treated according to the present invention;

FIG. 10 is a diagrammatic partial view of a jaw in which another aspectof the present invention is illustrated;

FIG. 11 is a diagrammatic lateral view of a masticatory and bitesimulator in which another aspect of the invention is illustrated; and

FIG. 12 shows a diagrammatic lateral view of a jaw of FIG. 11 in asurface mapping device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the figures, identical or similar parts or identically or similarlyfunctioning parts have the same reference numbers or are depicted in acomparable manner so that a person skilled in the art is able torecognize parts and their combinations, functions, and modes of actionspossibly solely by looking at the figures, by comparing said figuresand/or by reading the description below even if no reference isexpressly made or shown between the individual figures and/or betweenthe figures and the text.

First, a conventional measuring method will be explained so as toprovide insight into the functioning of the device involved. This typeof measuring method is used, for example, by the firm of DCS Forschungs-and Entwicklungs AG in Allschwil, Switzerland, and has been introducedto the public as early as in 1999. This measuring method has beenconsiderably improved by the present invention.

FIGS. 1 and 2 show a top view and a front view, respectively, in whichjaw K is being scanned. For example, five measuring lines S1, S2, S3,S4, and S5, one next to the other, are scanned. The five measuring lines51 to S5 overlap in areas B which are hatched in FIG. 1 a and omittedfor the sake of clarity in FIG. 1 b. FIG. 1 b serves only to illustratethe position of measuring lines S1 to S5 in the front view of jaw K andto show the direction of the scanning radiation which is denoted byarrows P. Overlapping regions B make it possible to assemble the data ofthe individual measuring lines by means of matching methods so as toform an overall image of jaw K.

FIGS. 1 c and 1 d, again shown as a top view and a front view,respectively, illustrate a variation of the prior technology describedabove based on the present invention. According to this method and usingthe appropriate devices, measuring lines S6, S7, S8, S9, S10, S11, S12,and S13 are generated, except that these lines are made up only ofso-called half frames, so that, although the number of measuring linesis greater than in the variation according to FIGS. 1 a and 1 b, thesemeasuring stripes are able to function with markedly fewer data. Theposition of measuring lines S6 through S13 is shown in the top view ofFIG. 1 c relative to jaw K. In FIG. 1 d, the directions of the radiationare diagrammatically denoted by arrows P1, P2, P3, and P4, usingmeasuring lines S6, S11, S13, and S10 as an example. In FIG. 1 c,overlapping areas B of the neighboring measuring lines are again shownin hatched representation. Because of the directions of radiation whichdiffer from prior art for the individual measuring lines, the dataobtained for jaw K are more precise, with the number of data and theamount of processing required being reduced with respect to prior artsince only half frames are used.

In FIG. 2 a, one single object to be measured in the form of a tooth Zis diagrammatically shown in a perspective view after placement inmeasuring pot M which, for this purpose, is filled, for example, with amodeling material into which the lower end of tooth Z is inserted (notshown).

For this object Z to be measured, the position of the measuring lines Sis diagrammatically shown in FIG. 2B, and FIG. 2 c shows the signalimage for one measuring line Sz in which only one measuring point Dx isobtained. In FIG. 2 b, the readout direction (line direction) isadditionally denoted by arrow A1. The sum of all measuring lines S formsthe area of chip C as the image mapping device which can be, forexample, a CCD chip or any other camera system.

In contrast, a measuring line S according to the present inventionproduces a plurality of measuring points, e.g., Dy1 and Dy2 or Dza toDzn, as illustrated in FIGS. 2 d and 2 e, which figures arerepresentations corresponding to those in FIGS. 2 b and 2 c. The readoutdirection in FIG. 2 d is indicated by arrow A2, and chip C and theposition of measuring lines S are thus rotated by 90° relative to priorart. This configuration according to the present invention produces twomeasuring points Dy1 and Dy2 in measuring line Sy. And the measurementin line Sz produces even a plurality of measuring points Dza to Dzn. Forthe purpose of the subsequent evaluation, the chip configuration ispreferably extrapolated and simulated by means of suitable software inthe same manner as in prior art (see FIG. 2 b). Per line, the readoutdirection which is again obtained in the same manner as in prior art,however, again contains several measuring points which can be computedfirst as point 1, subsequently as point 2, etc. Thus, although theamount of work required is reduced as a result of the fact that onlyhalf frames are used, this aspect of the invention leads to a greaternumber of data, which further increases the precision of this inventionrelative to prior art.

FIGS. 3 and 4 which are enlarged representations of a portion of FIG. 3illustrate surface mapping device 1 with laser optics 4 from which laserline beam L exits. The point of intersection of laser line beam L withthe rectangular image field F which exits from the lens definesmeasuring field F. Each object to be scanned must be passed through thismeasuring field F. This also applies to the embodiments according toFIGS. 5, 6, and 7 although this particular detail is not shown in thesefigures which concentrate on the other features. Thus, to avoidrepetitions, this aspect will not be mentioned again in the followingdiscussion of FIGS. 5, 6, and 7; however, the use of this technology isdeemed to be obvious to the person skilled in the art who will knowwhere and how to use it.

To avoid repetitions, the following discussion will by reference alsoinclude FIGS. 5, 6, and 7 to the extent that the design is identical orcomparable.

The “passage through” measuring field F is implemented by means of alinear guide 83 (or reference number 4′ in FIGS. 5 and 6). To be able toposition a plurality of individual objects, such as, in particular,teeth, within the measuring field, a rotating plate 33 (or referencenumber 5 in FIGS. 5, 6, and 7) rotates from measuring pot 84 tomeasuring pot 84 (in FIG. 5, the measuring pots are denoted by referencenumber 8). In FIG. 3, only two measuring pots 84 are sketched in by wayof an example (the same applies to FIG. 5, e.g., where only twomeasuring pots 8 are shown), but a total of, for example, sevenmeasuring pots could be mounted.

Once a measuring pot 84 (or 8 in FIG. 5) holding a tooth arrives in themeasuring field, the large rotating plate 33 (or 5 in FIGS. 5, 6, and 7)stops rotating. Thus, rotating plate 33 (or 5 in FIGS. 5, 6, and 7) onlyserves to position the pots 84 (or 8 in FIG. 5) holding the individualteeth and/or a jaw, which will be explained in greater detail below. Asalready explained above, the measurement as such is carried out by meansof a linear movement of measuring table 53 on the linear guide mounts 83or 4′ (FIG. 5).

This produces a measuring line which can see only one side of the toothto be scanned. To be able to obtain additional measuring lines fromadditional angles, pot 84 (or 8 in FIG. 5) located in the measuringfield can be rotated around its own axis between the individualmeasurement. This can lead, for example, to eight images, or, in otherwords, pot 84 (or 8 in FIG. 5) is rotated by 45° around its own axisbetween the measurements. Thus, in such a case, eight measuring linesfrom different angles are obtained. Portions of the thus obtainedsurface data appear in several measuring lines. By means of theseoverlapping areas, suitable devices or methods in the form, for example,of an already discussed matching software can assemble the individualmeasuring lines to form a complete 3-D surface image of a single tooth,thus ensuring a high precision of measurement.

These data now make it possible to mill the inside data record of adental crown. In addition to milling individual crowns, several singleteeth can also be combined to form a bridge. To be able to mill bridges,the spatial position of several single crowns relative to one anothermust be determined as fast as possible. For this purpose, a complete jawmodel is scanned in the same way as a single tooth. It is placed on anadditional rotating plate 26 which is provided in rotating plate 5 ofFIG. 5.

The result can be seen in the image of FIG. 8 (the direction of themeasuring lines is illustrated by five white lines (some of which, byway of an example, are denoted by 11, 12, and 13 while the others aresimply sketched in as lines). Although this result of the measurementdoes not include all data of the jaw, sufficient data for the outersurfaces are available so as to be able to automatically produce thesestructures with the data of the individual dental stumps.

Subsequently, suitable devices or processes are used to start a softwaresearch which leads to an agreement of the data. The result can be seenin the image of FIG. 9. The two highlighted data records [sic] of thefirst tooth at the top of the left side and of the next tooth in the jawmodel following the gap represent the referenced single teeth.

Below, additional improvements will be illustrated and explained.

With reference to FIGS. 5, 6, and 7, with FIG. 5 being a perspective topview and FIGS. 6 and 7 being perspective views of the same device frombelow, a rotating plate 5 serves to transport a number of measuring pots8 for single teeth for placement under the laser measuring setup(compare FIG. 3). This rotating plate 5 is driven by means of a frictionwheel 15 (see FIG. 6). The front of this friction wheel 15 is pressedagainst rotating plate 5 by means of a spring plate 24 (see FIG. 6).This compensates for the potential wear of a rubber surface or of therubber material of friction wheel 15.

The position of rotating plate 5 is determined by means of encoder disk28. In the case at hand, the disk is designed in the form of a plate 28(see FIG. 6) which has slots 100 precisely in those regions in which therequired stop positions are located. Slots 100 are detected by means ofa light barrier 33 (see FIG. 6). In a suitable device or by means of afeature that is incorporated into the process, a control softwareevaluates the light barrier signals and starts and stops the table orplate 5. Rotating plate 5 has seven positions/pots for single teeth. Ifmore than seven preparations/teeth are to be worked on (a maximum of 14teeth per jaw is possible), the work can be carried out in 2 batches.

Advantages of the devices described above:

-   -   extremely favorable production cost, available anywhere    -   no wear and tear    -   balance quality which ensures a quiet operation    -   exact knowledge of the positions

As an alternative to friction wheel 15, it is also possible to use, forexample, a belt pulley or a toothed belt.

As to the prior art, reference is hereby made to a scanner of the firmof DCS Forschungs-und Entwicklungs AG in Allschwil, Switzerland, whichwas first presented to the public at the 1999 IDS exhibit in Cologne.

In the prior art, rotating plate 5 which was toothed along its outerperiphery was used for the same purpose. The plate was driven by meansof a small toothed wheel made of plastic. The path segments/angles ofrotation were traversed by means of a number of steps which werepredetermined in the software. A feedback to the control to determinewhether the angle was in fact maintained did not exist. The plate wasable to hold 14 pots which made it possible to scan a maximum of 14stumps per jaw within one scan. This prior-art technology has thefollowing drawbacks:

-   -   teeth along the outer periphery make the plate expensive and not        readily available    -   the small plastic toothed wheel was subjected to considerable        wear    -   high noise level during operation    -   lack of feedback regarding the position along the path    -   the 14 pots required (instead of preferably seven pots provided        by this invention) are responsible for disproportionately high        costs in the improbable case that there are more than seven        connected dental stumps in one procedure; moreover, the 14 pots        require a lot of space and determine the size and weight.

The cost of the construction of the frame can be further reduced byadditional measures. Thus, the frame of the apparatus/device issuspended from two guide rods 83 (compare FIGS. 3 and 4). Thus, thecomplete frame of the apparatus comprises only two lateral parts 2(compare FIGS. 3 and 4), the guide rods 83 (compare FIGS. 3 and 4), andan optical plate (FIG. 5). Inaccuracies potentially caused by themechanical design of the linear rod guide are compensated for by thesoftware (e.g., by means of so-called “look-up tables”). A precisionspindle 94 (compare FIGS. 3 and 4) is attached to the side of the movingtable on which the laser setup is located. Thus, errors in the angle ofthe spindle have a lesser effect. Advantages of this setup include lowproduction costs, high precision, a markedly lower transport weight, anda more compact design.

As to the design mentioned above, ground linear guides with ball cagesinstead of 2 linear rod guides were used in the device produced by thefirm of DCS Forschungs- und Entwicklungs AG in Allschwil, Switzerland.This necessitated a massive 8-part frame construction of massive metalplates which had to be produced with high precision. For reasons ofspace, it had been possible to attach the drive spindle only on the sideof the moving table that was located opposite to the laser, which, giventhe free motion of the spindle, leads to errors in the angle.

The prior art device can be further improved by providing the laserdiode with protection against electric shock. For this purpose, thelaser optics, the laser diode, and the electronic control for the laserdiode are housed together in a metal housing. The advantage is improvedprotection of the diode, in particular against electrostatic chargesfrom the outside, and the fact that the exchange of parts is facilitatedin cases of needed repairs.

In the known prior-art device of the firm of DCS Forschungs- undEntwicklungs AG, Allschwil, Switzerland, the electronic components andthe diode are located in separate areas. After the housing of the deviceis removed, both components lie bare so that the service personnel cantouch these parts and thus damage the optical system.

In addition, other improvements compared to prior art are possible inthe manner in which jaw models are adjusted. To be able to optimallyadjust jaw models that are to be scanned, a template 54 (see FIG. 5) isneeded. Since jaw models have different diameters (e.g., for childrenand adults), the jaw model must be adjusted to the size required. Forthis purpose, for example, 3 different adjustment contours I, II, and IIare engraved or otherwise suitably placed on the transparent Plexiglasdisk from which template 54 is preferably made.

Furthermore, other improvements are possible, for example, by rotatingthe individual pots by 45°. Rotating plate 5 (FIGS. 5, 6, and 7)transports individual pots 8 to the measuring position just in front ofthe friction wheel 15. While rotating plate 5 moves, the frictioncontact between the pot 8 and the friction wheel 15 is automaticallygenerated. The novelty is that friction wheel 15 is made of rubber or atleast has a rubber bearing surface while the counterwheel 7 is made ofsolid metal. Advantages include a reduction in price, easiermanufacture, and longer life. The prior-art device manufactured by thefirm of DCS Forschungs- and Entwicklungs AG, Allschwil, Switzerland, hada friction wheel made of metal while all counterwheels were covered withO rings made of rubber. The disadvantage of such an arrangement is thatthe O rings wear out after a certain length of time and that theproduction cost is high.

Another aspect of the present invention will be explained by referenceto FIG. 10. This figure shows 3 dental stumps 101, each comprising aground portion 101 a and a residual tooth portion 101 b. The grinding isdone manually by a dentist and necessarily leads to undercuttings 102which, when looking at several adjacently positioned individual teeth ortheir stumps 101, differ as to shape, position, and size. To construct aplanned prosthesis 103, the overall contour of which is shown as abroken line by way of an example only on stump 101 completely on theleft side of FIG. 10, on dental stumps 101, a so-called cap 104 is firstproduced for at least one stump 101, which cap can, as a rule, beslipped over stump 101 in exactly one slip-on or clip-on direction asindicated by arrow E. In this manner, it is not possible for cap 104 tofill the undercuttings 102 since otherwise it would no longer bepossible for the cap to be slipped on. In the case demonstrated inconnection with the preceding practical example, 3 stumps are locatedside by side, and the 3 caps 104 thereon are combined to form a bridgeby connecting each adjacent cap 104 by means of a joint 105.

To shape the totality of all of caps 104, it is necessary to determinean optimum slip-on or clip-on direction which minimizes undercuttings102 which form, among other things, for example, because of the obliqueposition of one stump 101 relative to the other stumps 101, as isillustrated by stump 101 on the right side of FIG. 10.

This can be carried out in advance on the basis of the 3-D data obtainedfrom stumps 101. For this purpose, as already explained in detail in thepresent documents, a 3-D data record is generated by means of scanningas disclosed by the present invention and used for model calculations toidentify the optimum slip-on or clip-on direction. For this aspect ofthe method according to the present invention, different clip-ondirections are successively used as a basis, and the “dead space” causedby undercuttings 102 is determined for each of the results. The optimumslip-on direction A is obtained by identifying the variation with thesmallest “dead space.”

Especially as a result of an oblique position of a remaining stump 101,but also as a result of other imprecisions caused during the work by thedentist, it is possible for cases to arise in which a cap, relative to aresidual tooth region 101 b, would, in certain places, have to have awall thickness of 0 mm. In such a case, it is principally not possibleto produce a dental prosthesis. Before anything else can be done, time-and cost-intensive work must first be carried out on the tooth stump 101involved, and often it is not certain that this work will lead to auseful result.

In addition to the optimization of the slip-on direction E to minimizethe undercuttings or “dead spaces” 102 as provided by the presentinvention, the present invention can be used to further improve theapproach to the production of dental prostheses. By means of therecorded (scanned) 3-D data, it is possible to prepare recommendationsfor the treating dentist which tell him what kind of work should be doneon the dental stumps that would more likely lead to an improvement ofthe fit and stability of the prosthesis to be manufactured, includingwhat to do to markedly reduce the undercuttings or the “dead spaces”102. For this purpose, the scope of the method according to the presentinvention is extended so that relative to a recorded 3-D data record ofone dental stump 101 or a combination of several dental stumps 101, anoptimum clip-on direction for cap 104, in particular a combination of aplurality of caps 104 to form a bridge 106, is calculated provided thatchanges in the shape of the dental stump/the dental stumps 101 arepossible. Thus, the method and system according to the present inventionserve not only to make possible an adjustment to a given situation whencaps 104 or bridges 106 are produced and clipped on but also to change agiven situation so as to optimize the result, i.e., the prosthesis. Forexample, the method and system can make provision for the inclusion of agraphic display of the stumps, including, for example, specially dyedregions, for the finishing work, which display can serve as a basis fora dialogue between a dental lab and a dentist.

Furthermore, the invention in all of its embodiments described abovealso has the advantage of creating the possibility of a qualityassurance, including, in particular, the possibility of unambiguouslyconnecting given treatment results with the dentist who prepared thedental stumps by means of grinding or with the dental lab which producedthe caps/crowns/bridges. Thus, it will be possible for the first time tosettle questions of who bears the responsibility in cases of aninaccurate fit. Furthermore, it will be possible to advantageously makeuse of the fact that all data at the outset of a treatment as well asall data of the dental status at certain intervals can be continuouslyarchived in an especially simple and at all times readily accessiblemanner.

The method and its variations explained above by reference to FIG. 10are equivalent to appropriately designed devices by means of which thesemethods can be carried out so that any devices, with which the personskilled in the art would be immediately familiar on the basis of therepresentation of the methods in their general and specific embodiments,are deemed to have been disclosed in the present documents.

Another aspect of the present invention relates to the automaticgeneration of the masticatory surface of a dental prosthesis, takinginto consideration the counter bite (upper jaw to lower jaw). In thepractical example illustrated in FIGS. 11 and 12, the following stepswhich will be described below are provided:

1. Insertion and adjustment of upper and lower jaws 206 and 207 in amasticatory simulator or articulator 200 with adjusting joints 201 untilthe bite situation is simulated, as shown in FIG. 11. Supports 202/202 aand 203/203 a for upper and lower jaws 206 and 207, respectively, have adetectable spatial position. Supports 202/202 a and 202/203 a, forexample, have a defined zero position or a zero position with respect toeach other. Each support 202/202 a and 203/203 a has two parts andcomprises a supporting base 202 a and 203 a, each of which is stationaryaffixed to articulator 200, and a jaw support 202 and 203, to whichupper jaw 206 and lower jaw 207, respectively, are attached.

2. Reading in/recording, e.g., 6 degrees of freedom:

-   -   2 possibilities:        -   reading a scale manually        -   reading out encoders

Using articulator 200, the optimum/correct position of supports 202/202a and 202/203 a, i.e., actually of the support base 202 a and 203 a, isdetermined while taking into account upper and lower jaws 206 and 207,respectively, as shown in FIG. 11. This can take place automaticallywith scales (not shown) which are provided on and are attached toarticulator 200 or by means of position and phase-angle encoders (notshown). It should be noted that articulator 200 preferably allows analignment of upper and lower jaws 206 and 207 with respect to each otherin preferably six degrees of freedom.

3. Insertion of the respective jaw support 202 or 203 with the upper jawmodel 206 or the lower jaw model 207 into a support 205 incorrespondence with the support bases 202 a and 203 a of scanner 204according to FIG. 12, whereby the spatial position of support 205relative to the measuring system or the data system of scanner 204 isknown.

4. Referencing is subsequently carried out by means of software.

5. Proposal from the database for the masticatory surface (e.g.,incisor)

-   -   Automatic adjustment of the database model to the counter bite        situation    -   Search for contact points with envelope data    -   Matching the masticatory surface to the internal data record

Alternatively: record the position of the “articulated” jaw by means ofscanning a portion of the articulated jaw and subsequently match thedata of the upper and the lower jaws with these partial data records toproduce the bite position.

The aspect of the invention explained with reference to FIGS. 11 and 12is also to be considered as having been disclosed as part of the methodand the device since a person skilled in the art can recognize suitabledevices in general or special embodiments from the explanations givenabove.

The present invention is explained in the description and in thedrawings on the basis of the practical examples solely by way ofexamples and is not limited thereto but comprises all variations,modifications, substitutions, and combinations that the person skilledin the art can gather from the present documents, in particular theclaims and the general explanations in the introduction of thisdescription and the description of the practical examples and therepresentations thereof in the drawing, and can combine, based on his orher expert knowledge as well as on prior art, in particular whenincluding the complete disclosure contents of the previous applicationscited in this description. In particular, all individual features andpossibilities of the embodiments of the invention and the practicalexamples can be combined with one another.

What is claimed is:
 1. A device for mapping a surface of a jaw model,said device comprising: a template for adjusting said jaw model to bemapped, wherein said template comprises different adjustment contours,said adjustment contours being suitably placed on a material from whichsaid template is made, and wherein said different adjustment contoursare adapted such that jaw models of different diameters may be adjusted.2. The device as set forth in claim 1, wherein said template is made oftransparent plexiglass.
 3. A method for mapping a surface of a jawmodel, said method comprising: adjusting a jaw model to be mapped with atemplate, wherein said template comprises different adjustment contours,said adjustment contours being suitably placed on a material from whichsaid template is made, and wherein said different adjustment contoursare adapted such that jaw models of different diameters may be adjusted.4. The method as set forth in claim 3, wherein said template is made oftransparent plexiglass.
 5. The device of claim 1, wherein said adjustcontours are engraved into said material from which said template ismade.
 6. The method of claim 3, wherein said adjust contours areengraved into said material from which said template is made.
 7. Adevice for mapping a surface of a jaw model, said device comprising: atemplate adapted to adjust said jaw model to be mapped, wherein saidtemplate is situated above a rotating plate adapted to receive said jawmodel, wherein said template is comprised of a transparent materialcomprising a plurality of adjustment contours engraved therein, whereineach of said plurality of adjustment contours comprises a differentsize, and wherein each of said plurality of contours is adapted toposition a jaw model in a correct position for scanning based on adiameter of said jaw model.